1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method each for performing heat processing, for example, for a semiconductor wafer immediately after it has been coated with a resist.
2. Description of the Related Art
In a photoresist process in semiconductor device fabrication, for example, a resist is applied to a substrate, for example, a semiconductor wafer (hereinafter, referred to as xe2x80x9ca waferxe2x80x9d ) or the like, and is exposed to a predetermined pattern, and thereafter a developing solution is supplied to the wafer to perform developing processing.
Such processing is performed by a system constituted by connecting, for example, a coating and developing processing apparatus for performing resist coating and developing processing to an aligner. The coating and developing processing apparatus includes processing units for individually performing a series of processing necessary for coating and developing processing for a wafer, for example, hydrophobic processing (adhesion processing) for enhancing fixedness of a resist, resist coating processing for applying a resist, heat processing for heating the wafer after the resist coating to dry and cure the resist, heat processing for heating the wafer after exposure at a predetermined temperature, developing processing for performing developing processing for the wafer after the exposure, and the like, and the wafer is transferred between these processing units by a wafer transporter.
However, the aforesaid resist, for example, a chemically amplified resist, immediately after being applied onto the wafer contains an aid generator having a catalysis by, for example, a thinner which is a solvent or by photochemical reaction, a quencher which is a dissolution inhibitor, a polymer chain protecting group, and the like, and it is necessary to volatilize the thinner in particular out of these to cure the resist in a heat processing step after the resist coating.
In a typical heat processing step, however, the wafer is processed at a high temperature, causing a case in which the polymer chain protecting group is broken, the acid generator is not uniformly dispersed in the resist, or the quencher is not uniformly formed on the front face of the resist.
On the other hand, as a circuit pattern is made finer in recent years, there is a tendency to use, as a light source for exposure, a light source with an extremely short wavelength at a level of, for example, an F2 laser light source, for example, 157 nm. If O2, O3, organic substances, H2O, and the like are contained in the air during the exposure, light of such a light source with a short wavelength is absorbed by the substances and thus the amount of light from the light source reaching the resist extraordinarily decreases. On addition, in the above-described heat processing, O2, O3, and the like, strongly tend to adhere to the front face of the resist, thus causing exposure to be susceptible to failure due to the substances in the exposure step.
An object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of performing thermal processing for a substrate so that an acid generator is dispersed in a resist, or a dissolution inhibitor is uniformly formed on the front face of the resist without breakage of a polymer chain protecting group.
Another object of the present invention is to provide a substrate processing apparatus and a substrate processing method in which O2, O3, or the like is prevented from adhering to the front face of the resist after heat processing.
To attain the above-described objects, the substrate processing apparatus according to a first aspect of the present invention is a substrate processing apparatus for performing heat processing for a substrate coated with a resist containing at least one substance out of an acid generator, a dissolution inhibitor, and a polymer chain protecting group, and a solvent, comprising: a processing chamber having a space capable of being tightly closed; a plate disposed in the space for mounting thereon the substrate coated with the resist; a pressure reducing device for reducing a pressure in the tightly closed space; and a controller for controlling the pressure reducing device to hold a pressure at a level at which the solvent contained in the resist volatilizes and the substance practically remains in the resist.
The substrate processing apparatus according to a second aspect of the present invention is a substrate processing apparatus for performing processing for a substrate coated with a resist containing at least one substance out of an acid generator, a dissolution inhibitor, and a polymer chain protecting group, and a solvent, comprising: a processing chamber having a space capable of being tightly closed; a processing plate disposed in the space for processing the substrate coated with the resist at a room temperature or less; a pressure reducing device for reducing a pressure in the tightly closed space; and a controller for controlling a temperature of the processing plate and a degree of vacuum in the space to hold a temperature and a pressure at levels at which the solvent contained in the resist volatilizes, and the substance practically remains in the resist.
The substrate processing method according to a third aspect of the present invention is a method of performing heat processing for a substrate coated with a resist containing at least one substance out of an acid generator, a dissolution inhibitor, and a polymer chain protecting group, and a solvent, comprising the steps of: (a) performing heat processing for the substrate at a reduced pressure and a temperature at levels at which the solvent contained in the resist volatilizes and the substance practically remains in the resist; and (b) performing cooling processing for the processed substrate.
In the present invention, since, for example, the heat processing for the substrate is performed at a reduced pressure and a temperature at levels at which the solvent contained in the resist volatilizes and the acid generator, the dissolution inhibitor, and the polymer chain protecting group practically remain in the resist, the thermal processing can be performed for the substrate so that the acid generator is uniformly dispersed in the resist, or the dissolution inhibitor is uniformly formed on the front face of the resist.
These objects and still other objects and advantages of the present invention will become apparent upon reading the following specification when taken in conjunction with the accompanying drawings.